Nickel, titanium, cobalt, iron, and manganese permanent magnet



Patented Jan. 1a, 1938 UNITED STATES PATENT OFFICE NICKEL, TITANIUM. COBALT, IRON, AND MANGANESE PERMANENT MAGNET Kotaro Honda, Sendai, Japan No Drawing. Original applications November 13,

1933, SerialNo. 897,874, and July 18, 1934, Serial N0. 735,898. Divided and this application June 6, 1935, Serial No. 25,345.

6 Claims.

a very high coercive force and long durability.

This forms a division from application Ser. No. 735,898 filed July 18, 1934 and also from the parent application Ser. 'No. 697,874 filed November 13, 1933, both pending.

Heretofore commonly used magnet steels such as tungsten steel, chrome steel and the like have comparatively small coercive force of only to gausses and if such alloy steels are used as a permanent magnet they lack durability and are especially unsuitable for a magnet of smaller dimension-ratio, that is, having a small ratio of the length and diameter. Moreover, such alloy steels are greatly aiiected by temperature variations and mechanical shocks and show unstable magnetic properties.

This invention is to obviate the above mentioned defects and to provide an alloy which is well adapted for a permanent magnet of a smaller dimension-ratio, and possesses stable magnetic properties for temperature changes and mechan ical shocks and has particularly 'high' coercive force.

The alloy of this invention can be obtained by melting together nickel, titanium, cobalt, manganese and iron in the proportion of 3 to 50% nickel, 8.1 to 50% titanium, less than 60% cobalt, .1 to 20% manganese and the remainder substantially iron. The preferred composition of the alloy may be of 10.1 to 40% nickel, 8.1 to 40% titanium, less than 50% cobalt, .1 to 20% manganese and the remainder iron. The molten product may be cast in a suitable mold or sucked up into a tube of refractory material to give a desired shape. The castproduct is preferably annealed at a suitable temperature such as 500 to 800 C. to give it stability.

As above described, though the alloy 01 this invention may be obtained by melting together iron, nickel, cobalt, titanium and manganese at a proper proportion, yet it is more convenient in practice to use iron or mild steel, nickel, cobalt, manganese and term-titanium.

As for example, the following two alloys of In Japan May this invention show magnetic properties as follows:

Nickel 1 1 16 Titanium 10% 11% 5 Cobalt 20% 28% Iron Remainder Remainder Residual magnetic induction (gausses) 9000 7500 Coercive f o r c e 10 (gausses) 250 830 Such magnetic properties are obtained by casting the alloys and aiterwards annealing them at about 670 C. for two hours. It will be recognized that the above alloys show particularly high coercive force.

The alloys of the present invention may also contain manganese in the proportion of less than 20% for further increase of the residual magnetic induction and the coercive force.

Accordingly the alloy of this invention is well adapted for the material of permanent magnets in general and more especially of smaller dimension-ratio and it has very stable structure at a temperature below about 700 C., and its magnetic properties are not substantially afiected by the change of temperatures and thus it is most suitable for the material of permanent magnets for fine instruments and also for heat resisting permanent magnets.

I claim:.

1. An alloy containing about 11% nickel, 10% titanium, 20% cobalt, .1 to 20% manganese, and the remainder iron and a small amount of impurities, characterized by a coercive force of about 250 gausses or more.

2.'An alloy containing about 16% nickel, 11% titanium, 28% cobalt, .1% to 20% manganese and the remainder iron and a small amount of impurities, characterized by a coercive force of about 830 40 gausses or more.

3. A permanent magnet formed of an alloy containing 10.1% to 40% nickel, 8.1% to 40% titanium, 0.01% to 50% cobalt, .1% to 20% manganese and at least 20% iron and a small amount of im 45 purities, characterized by a coercive force in the neighborhood of 250 gausses or more.

4. A permanent magnet formed of an alloy containing 3% to 50% nickel, 8.1% to 50% titanium, .1% to 50% cobalt, .1% to 20% manganese and at 50 least 20% iron and a small amount oi! impurities, characterized by a coercive force in the neighborhood of 250 gausses or more.

5. A permanent magnet formed oi an alloy containing about 11% nickel, 10% titanium, 20% cobalt, .1 to 20% manganese, and the remainder iron and a small amount of impurities, characterized by a coercive force of about 250 gausses or more. I

' cobalt, .1% to 20% manganese and the remainder iron and a small amount oi impurities, characterized by a coercive force of about 830 gausses or more.

KOTARO HONDA. 

